Presently, many mobile devices are equipped with sliding parts, such as sliding covers, that make it possible to expand the user interface surface of the device while still keeping the device compact in a closed configuration. The sliding part of typically moves along rails installed in the sliding part and in a base part. Manufacturing such devices requires a high level of control over clearances between the rail parts. Ideally, the sliding part should be able to move freely without unnecessary friction between the rail parts, but at the same time any extra wobbliness between the parts is undesirable.